This file points to 6 pairs of files of the form    "?bt*"
("?" is a single-character wildcard and "*" is a multiple-character wildcard.)

Crossing File	Backbone Overlay
1bt3_A	1bt3_A_sse
1bte_A	1bte_A_sse
1btk_A	1btk_A_sse
1btn	1btn_sse
2btv_A	2btv_A_sse
3bta_A	3bta_A_sse